1. Field of the Invention
This invention relates to a polyolefin-base resin composition incorporated with vegetable fibrous materials in fiber form containing fiber-form cellulose as major constituent. Such a resin composition is conveniently used in industrial commodities such as the casing for an air conditioner of cars.
2. Description of the Related Art
There is described in Japanese patent publication Nos. 36,134/77 and 9,576/81 a material of polyolefin resins incorporated with a vegetable fibrous material containing cellulose as major constituent, such as wood flour, rice hulls, or waste paper. Such a material is actually used but to a limited extent. However, because of their poor processability, conventional composite materials comprising polyolefin-base resins incorporated with vegetable fibers containing cellulose as major constituent are unsuitable for general use and few of them are being in use. For instance, if such a molding material is used in molding an article of a large size or of a small thickness by the most popular method of injection molding, it will be found difficult to fill the mold completely with the material. The reason for this was found by the present inventor to be attributable to the problem of mold flow of the material. When the molding temperature is increased to improve the mold flow, there occurs deterioration of the vegetable fiber in the composite material, leading to the emission of malodor or the decrease in physical properties which renders the composite material unable to manifest full advantage of its characteristics. As a consequence, the composite, if remains as such without improvement, will be confined in its use within a narrow range including vacuum forming.
The primary object of this invention is to overcome the above difficulties and to provide a polyolefin-base molding composition excellent in processability and physical properties.